77 lines
2.4 KiB
TypeScript
77 lines
2.4 KiB
TypeScript
import { BEACH, ICECAP, LIGHT_FOREST, MOUNTAIN, WATER } from "./data";
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import { IslandGrid } from "./grid";
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export type IsDone = boolean;
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export type LobeGenerator = () => IsDone;
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export type LobeGeneratorConstructor = (
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islands: IslandGrid,
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basePos: number
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) => LobeGenerator;
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/** form mountain with icecap */
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export const BIG_MOUNTAIN: LobeGeneratorConstructor =
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(islands: IslandGrid, basePos: number) => () => {
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const mountainTiles = islands.floodSearch(
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basePos,
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(tile) => tile > MOUNTAIN
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);
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islands.dropWithin(mountainTiles);
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return mountainTiles.some((pos) => islands.data[pos] == ICECAP);
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};
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/** form low-lying beach */
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export const BEACH_LOBE: LobeGeneratorConstructor =
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(islands: IslandGrid, basePos: number) => () => {
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const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
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const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
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islands.dropWithin(shoreTiles);
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return true;
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};
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/** form forested zone */
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export const FOREST_LOBE: LobeGeneratorConstructor =
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(islands: IslandGrid, basePos: number) => () => {
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const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
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// grow shore
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const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
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islands.dropWithin(shoreTiles);
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// seed beach
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const beachTiles = islandTiles.filter((pos) => islands.data[pos] == BEACH);
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islands.dropWithin(beachTiles);
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// expand forest
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const forestLobe = islands.floodSearch(basePos, (tile) => tile > BEACH);
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const forestTiles = forestLobe.filter(
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(pos) => islands.data[pos] == LIGHT_FOREST
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);
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islands.dropWithin(forestTiles);
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islands.dropWithin(forestTiles);
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islands.dropWithin(forestTiles);
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return true;
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};
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/** form low-lying beach with eroded sections */
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export const ERODED_LOBE: LobeGeneratorConstructor =
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(islands: IslandGrid, basePos: number) => () => {
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const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
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const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
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islands.dropWithin(shoreTiles);
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// erode
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if (islandTiles.length > 1) {
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const erodePos = islandTiles[islands.rng() % islandTiles.length];
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islands.data[erodePos] = Math.max(islands.data[erodePos] - 1, WATER);
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}
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return true;
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};
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export const BIG_ISLANDS = [BIG_MOUNTAIN];
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export const ALL_ISLANDS = [BIG_MOUNTAIN, BEACH_LOBE, FOREST_LOBE, ERODED_LOBE];
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